Air circulating fan



Dec- 13, 1949 J.' H. BECKERT AIR CIRCULATING FAN Filed June l, 1946 INVENTOR. BY bhw Hfe/(5K7 Patented Dec. 13, 1949 UNITED STATES PATENT OFFICE AIR CIRCULATING FAN John H. Beckett, Los Angeles, Calif.

Application J une 1, 1946, Serial N'o. 673,179

8 Claims.

This invention relates to air circulating fans and has as its general object to provide va fan that is adapted to circulate air in all directions.

A specific object of the invention is to provide a fan adapted to deliver` air from both the periphery and the `side area thereof.

Another object of the invention is to provide a fan that is adapted to deliver air from the entire Aside area thereof including the central reg1on.

A further object `of the invention is to provide a pair of symmetrically arranged impellers adapted to cooperate to deliver air in substantially all directions to produce a movement of air generally similar to an expanding globe.

Another object of the invention is to provide a fan that is convertible from a pedestal type to a table type fan, said fan including a member which, in the pedestal arrangement, serves as a deflector for spreading laterally the air that would otherwise be delivered downwardly from the fan, and having the additional function rof providing a base for the fan when it is converted into a table type fan.

Other objects will become apparent in the ensuing specifications and appended drawings in which:

Fig. '1 is a side view of a fan embodying my invention;

Fig. 2 is an end view of one of the impellers of the fan; and

Fig. 3 is a plan view of the impeller shown in Fig. 2.

As an example of one form in which the invention may be embodied, I have shown inthe drawings an air circulating fan adapted to be employed for producing a gentle movement, in all directions, of air in a room or other oonfined air space. The fan has a pedestal including an upright 4 and a base 5 that is adapted to rest upon a floor surface. The upright 4 is tubular and supports `an extension shaft 9 that is telescoped therein and is adapted to be secured in a plurality of adjusted positions by means of a hand screw 'l threaded through a boss 8 in the upright 4 and engaging the extension shaft 6. The upper end of the extension shaft 6 is threaded, as at 9, into a boss I0 that is formed in the center of an air deflector Il. The air deflector I I includes a bottom I2 that is adapted to rest upon a flat surface when the pedestal is detached from the deector, and includes a generally conical deflector wall I3 rising from the bottom I2 and merging into a post I4 on the upper end of which is supported an electric motor I5.

'The motor I5 has a shaft I6 extending therethrough and projecting at both ends. A pair of impellers I'I are mounted upon the respective projecting shaft ends.

Each impeller II includes a hub I8 by means of which it is mounted upon the shaft I5, and a plurality of blades arranged symmetrically with respect to each other and to the hub axis. These blades are shaped so as to deliver air peripherally and axially.

Each of the rotor blades includes an air duct I9 shaped generally similar to a Cornucopia, having an inlet 20 and an outlet 2|. The inlet 20 is located in the forward face of a respective blade, and the outlet 2l is located ahead of the forward face of the opposite blade. At its inlet end the duct I9 is flared or belled outwardly to a maximum cross-sectional area, and it gradually decreases in cross-sectional area from the inlet 20 to the outlet 2 I.

The axis of each duct I9 is spiral shaped, in a plane normal to the axis of the shaft It, and gradually approaches the shaft I6 from the inlet 2'0 lto the outlet 2l. The spiral axes of the two ducts lie rin the same plane. The outlet 'end of each duct is extended into a space defined between the hub I8 and the inlet end of the other duct and is so constructed and arranged that air emitted therefrom will flow outwardly from the fan and substantially parallel to the major axis of the shaft I6.

Radiating in an arc of somewhat more than degrees .from each duct inlet 29 is a fan blade including an axially extending portion 22, a radially extending portion 23, and a curved intermediate portion 24 joining the portions 22 and 23.

These three blade portions are swept rearwardly with reference to the direction of blade movement and collectively present a composite forward surface that is generally frusto-conical. That is, from the inlet Z9, the blade portion 22 is inclined rearwardly and axially, the blade portion 23 is inclined rearwardly and radially outwardly, and the blade portion 24 is inclined rearwardly and in a direction intermediate the axial and radial. Consequently, the air encountered by the inclined surfaces will be thrown off the rotating blades in all directions throughout a substantially hemispherical surface of revolution of a fan mpeller, beginning with a direction substantially parallel to the axis of the shaft I9 (as indicated by the arrow 25) and terminatv ing in a .radially `outward direction substantially 3 normal to the axis of the shaft I6, as indicated by the arrow 26. The intermediate directions of air movement are indicated by arrows 21, 21 and 21".

Each duct I9 has, adjacent the motor I5, an inner wall 28 which extends to the hub I8 in a plane normal tothe axis of the shaft I6.

'I'he inner wall 28 has a curved portion 29 following the contour of the motor l5. From this curved portion, the inner wall extends radially outwardly as at 30 to merge with the peripheral wall 3| of the duct. From the peripheral l wall 3| an outer wall 32 extends inwardly toward the hub |8. These wall portions 28, 29, 30 and 3| dene a duct inlet 2E.

Each blade portion 23 is projected axially inwardly (toward the opposed impeller) beyond the inner wall portion 38, as at 33, and this axially inwardly projecting portion 33 terminates in a forwardly extending ange 34. each blade portion 23 is projected outwardly beyond the outer extremity of the flange 34, in order that the air currents (25) thrown from the tips of the blades of the opposed impellers may be free to, and will tend to move toward each other to an extent that is restricted only by the inward movement of air into the fan, indicated by the arrows 35.

The outlet 2| of each duct IS is directed rearwardly (with reference to the direction of rotation of the impeller) in a position to discharge against the inner, inclined face 22a of the adjacent blade member 22. The air discharged against the inclined face 22a is deflected axially outwardly from the motor I5.

The two fan impellers are mounted on the shaft E6 in axially registered relation, i. e. with the blade tips 23 of the opposed iinpellers lying in common planes.

In the operation of my improved air circulating fan, there will be an induction or inward movement of air in an equatorial plane lying midway between the rotational paths of the two impellers, as indicated by the arrow 35. This inwardly moving air will come above and from both sides of the fan as viewed from an end thereof (along the axis of rotation). The forwardly moving flanges 3ft will function to divide this zone of inwardly moving air from the zones l of outwardly moving air indicated by the arrows 25, 26, 2l, and to prevent air being thrown axially inwardly from the blade portion 33 into this zone of inwardly moving air. Such axially inward movement would short circuit the circulation of air between the Zones of inward and outward movement, and greatly reduce the eiiciency of the fan.

The edges of the flanges 3-5 and of the blade portions 22, 23, 2&5 are rounded as indicated as at 36 and 3l' respectively in order to inhibit turbulence of air movement around these edges.

The air currents moving inwardly at 35 will spread axially outwardly as they meet the surface of the motor l5, into the path of movement of the duct inlet 2|] and the inner regions of the impeller blades.l A portion of the air thus presented to each oncoming blade will be scooped up by the inlet 2|), and the remainder will be engaged by the areas of the blades immediately surrounding the inlet 2D and thence will be thrown outwardly in all directions as indicated by the arrows 25, 28, 21. Because of the increasing speed of blade movement toward the outer portions 23 of the blades, there will be a tendency The tip of -dicated by the arrows 39.

for the majority of the air to be thrown radially outwardly. In order to offset this tendency, and to equalize the ilow of air in all directions, I have provided the duct I9 which scoops up a substantial portion of the inowing air, at the forward face of one blade, passes it around to the forward face of the other blade, and discharges it axially as indicated by the arrow 38. The region of discharge from the outlets 2| is directly adjacent the hub |8, thereby providing concentrated air currents close to the axis of rotation. The inlets 20 are disposed directly in the path of travel of the inflowing currents to the forward faces of the impeller blades, thus inducing a maximum inflow of air into the ducts I9. The convergence of the ducts I 9 from the inlets 26 to the outlets 2| causes the air currents flowing therethrough to be speeded up. Consequently, the air currents discharged at 38 will be relatively high velocity air currents and will tend to drag the adjacent air currents being thrown off the blade portions 22 at 25, inwardly toward the axis of rotation. The net result is a substantial increase in axial movement (as compared to what would be possible in the absence of the ducts |9) and a corresponding decrease in radial air movement. This decrease in radial air movement results from the divergence into the ducts I9 of air that would otherwise be thrown outwardly by the blade portions 23. Consequently, my improved fan will produce a balanced ow of air in substantially all directions. Such air movement will be relatively gentle as contrasted to the forcible shaft of air thrown off by the conventional cooling fan. Set in the middle of a room, my circulating fan will produce a gentle circulation of air in substantially all directions on both sides of the medial plane of inward air movement 35. As the outwardly moving air currents gradually lose velocity, they will, at a distance from the fan, circulate back toward the equatorial plane of the air currents 35 and thence return to the fan along this plane.

Since a directly downward movement of air is not desirable, I have provided for the outward deflection of the downwardly moving air currents by the deilector base These outwardly deilected downwardly moving air currents are in- By unscrewing the shaft 6 from the boss 9, it becomes possible to utilize the deflector as a base for supporting the fan upon a table or the like.

As an alternative form of construction, it is J possible to utilize the post I4 as an air duct for the induction of air drawn through suitable inlet apertures in the base H. Air thus passed up'- wardly through the post I 4 can be passed outwardly through suitable outiet apertures in the vcasing of the motor |5, directly into the paths of revolution of the duct inlet 2B. In passing through the motor I5, the induction currents serve the additional function of cooling the motor. With the air inducted in this manner, it is no longer necessary for the air currents to flow inwardly along an equatorial plane 35, and the radially projecting air currents 26 may actually join each other from the opposed impellers.

While I have shown and described a pair of impellers each comprising two blades, it is to be understood that each impeller may embody agreater number of blades, with each duct |53 having an inlet in the forward face of one blade and its outlet in the forward face of a succeeding blade.

I claim as my invention:

1. In an air circulation fan, a motor having a shaft projecting from both ends thereof, a pair of fan impellers, one mounted on each projecting end of said shaft, each of said impellers including a plurality of blades and a corresponding number of spiral air transfer ducts each having an inlet in the forward. face of one blade and an outlet disposed forwardly of a succeeding blade, the blade surface impinged by the discharge from said outlet being being inclined so as to deiiect said discharge outwardly and substantially parallel to the axis of revolution of the impeller, each impeller so shaped that air is discharged therefrom over a range of 180.

2. In an air circulation fan, a motor having a shaft projecting from both ends thereof, a pair of fan impellers, one mounted on each projecting end of said shaft, each of said impellers including a plurality of blades and a corresponding number of spiral air transfer ducts each having an `inlet in the forward face of one blade and an outlet disposed forwardly of a succeeding blade, said outlet being disposed closely adjacent the hub of the impeller, the blade surface impinged by the discharge from said outlet being inclined so as to deflect said discharge outwardly and substantially parallel to the axis of revolution of the impeller, each impeller so shaped that air is discharged therefrom over a range of 180.

3. In an air circulating fan, a motor and a pair of impellers carried and driven by opposite ends of said motor, each impeller including a plurality of air transfer ducts and a corresponding number of impeller blades each having a forward region beginning with the inlet of one of said ducts and having blade portions swept rearwardly from said duct inlet in both axial and radial directions, each duct having an outlet arranged to discharge ahead of a blade succeeding the blade in which its inlet is located, the air ejected from said outlet impinged on the succeeding blade and moving outwardly from said impellers substantially parallel to lthe axis of rotation of said impellers.

4. In an air circulating fan, a motor and a pair of impellers carried and driven by opposite ends of said motor, said impellers each comprising a plurality of air transfer ducts each having an inlet facing in the direction of impeller rotation and an outlet adjacent the impeller hub, and a corresponding number of impeller blades each having an inner and a forward portion beginning with one of said duct inlets, and having blade portions swept rearwardly (with reference to the direction of rotation) in both axial, radial and intermediate directions.

5. In an air circulating fan, a motor and a pair of impellers carried and driven by opposite ends of said motor, said impellers being symmetrically opposed vto each other and each including a plurality of air transfer ducts each having an inlet facing in the direction of impeller rotation and an outlet disposed adjacent the impeller hub, each impeller including a corresponding number of blades each having an inner, forward region commencing with a duct inlet, an axially extending portion commencing just rearwardly of the outlet of another duct and swept rearwardly and axially therefrom, and a radially extending portion swept rearwardly and radially from the periphery of the associated duct inlet.

6. A fan as defined in claim 5, wherein said radially extending portion has a side region projecting axially inwardly toward the opposed impeller and terminating in a forwardly extending flange.

7. A fan as defined in claim 5, wherein said radially extending portion has a side region projecting axially inwardly toward the opposed impeller and terminating in a forwardly extending flange, said axially inwardly projecting blade portions of opposed impellers being fitted around the periphery of the motor.

8. An air circulating fan as defined in claim 9, wherein said duct has inner walls that are tted to the curved contour of the outer surface of said motor.

JOHN I-I. BECKERT.

REFERENCES CITED The following references are of record in the 

